Question

Mention the causative agents of DNA lesions in the human body that can lead to cancer.

Short answer

Answer: The causative agents of DNA lesions that can potentially lead to cancer include: 1. Ultraviolet (UV) radiation, which creates DNA lesions called pyrimidine dimers, causing mutations if not accurately repaired; 2. Ionizing radiation, such as X-rays and gamma rays, which cause single and double-strand breaks, as well as base modifications in DNA; 3. Chemical carcinogens like tobacco smoke and aflatoxins, which can cause various types of DNA damage and lead to cancer development; 4. Viruses, such as HPV and HBV, which cause DNA damage by integrating their viral DNA into the host genome, disrupting normal cellular functions; 5. Spontaneous mutations, which occur naturally or as a result of errors in DNA repair mechanisms, causing DNA damage that may accumulate over time and potentially lead to cancer.

Step-by-step solution

1. List the causative agents of DNA lesions

There are several factors and agents that can cause damage to the DNA, increasing the risk of cancer. Some of these factors include: 1.1 Ultraviolet (UV) radiation 1.2 Ionizing radiation 1.3 Chemical carcinogens 1.4 Viruses 1.5 Spontaneous mutations

2. Describe ultraviolet radiation

Ultraviolet (UV) radiation, particularly UVB, is a significant cause of DNA damage. UV radiation mostly comes from sunlight and plays a major role in causing skin cancer. UV radiation creates DNA lesions called pyrimidine dimers, which can cause mutations in the DNA if not accurately repaired. This may lead to uncontrolled cell growth and eventually to cancer.

3. Describe ionizing radiation

Ionizing radiation, such as X-rays, gamma rays, and nuclear radiation, can damage the DNA by causing single and double-strand breaks, as well as base modifications. These can cause errors in DNA replication and repair, which may lead to the development of cancer over time.

4. Describe chemical carcinogens

Chemical carcinogens are chemicals that can cause DNA damage, either directly or after being metabolized within the body. Examples include tobacco smoke, polycyclic aromatic hydrocarbons (PAHs), and aflatoxins. These chemicals can cause various types of DNA damage, such as adduct formation, strand breaks, and other modifications, potentially leading to cancer development.

5. Describe viruses

Some viruses can cause DNA damage by integrating their viral DNA into the host genome. This integration may disrupt the normal cellular functions, including DNA replication, and lead to cancer. Examples of viruses that can cause cancer include the human papillomavirus (HPV), hepatitis B virus (HBV), and human T-cell leukemia virus (HTLV).

6. Describe spontaneous mutations

Spontaneous mutations can occur naturally during DNA replication or as a result of errors in DNA repair mechanisms. These mutations can cause DNA damage, which may accumulate over time and potentially lead to cancer. Examples of spontaneous mutations include base substitutions, insertions, and deletions.